In a metal belt fitting described in Japanese Patent No. 3281226, an elongated hole is formed to a base plate, and a belt of a seatbelt device is inserted through the elongated hole. A ridge is formed at the periphery of the elongated hole of the base plate, and the ridge configures an outer peripheral face of the elongated hole. The material of the metal belt fitting is high tension steel plate.
In cases in which the plate thickness dimension of the base plate of the metal belt fitting is reduced, the surface area of a portion configured by the base plate at the outer peripheral face of the elongated hole is reduced, and since the surface area of the outer peripheral face of the elongated hole is reduced, the contact surface area of the belt with the outer peripheral face of the elongated hole is reduced.